The subject invention relates generally to an apparatus and method of converting an image on a transparency to line art and more particularly, but not by way of limitation, to the use of photographic film wherein the image on the film is optically converted to line art on a recording medium for microfilming the line art.
In U.S. Pat. No. 3,828,356 to Wiers a device is disclosed wherein an optical system performs a spatial fourier transform of recorded data. Also the use of a laser in an optical system for providing a beam of high energy light is disclosed in U.S. Pat. No. 3,556,661 to Hepner, U.S. Pat. No. 2,920,951 to Chovan, and U.S. Pat. No. 2,924,066 to Shapelle.
None of the above mentioned patents disclose the unique combination of structure for producing line art from an image on a transparency and the method as described herein.
The United States military along with commercial users of technical manuals have begun to require microfilming of the manuals so that these documents may be more easily stored. The half tone photographic process presently used for illustration in these manuals is not suitable for microfilming. Therefore, the solution in microfilming full tone and half tone photographs was solved by the manual tracing of the photographs of interest. It can be appreciated that this technique required substantial drafting time and costs involved to meet the microfilming requirements. The subject invention through optical processing techniques eliminates substantial drafting time in the conversion of continuous tone and half tone photographs to line art for microfilming.